The most innovative new music is being commissioned for Hollywood soundtracks. Joby Talbot, a modern composer who has scored the music for TV's The League of Gentlemen and arranged for The Divine Comedy, is currently at work on the soundtrack for a Disney film of The Hitchhiker's Guide to the Galaxy, Douglas Adams' cult novel that informed the psyches of so many science-fiction-obsessed, bespectacled boys in need of a bit of fantasy in the early 1980s.

For Talbot, the commission is a dream come true: he was such a boy. "Some people can recite the Koran. I can recite The Hitchhiker's Guide to the Galaxy," says Talbot, who has just woken up from a midday nap after a sleepless night caused by his two-year-old son. We are at his flat in Camberwell, southeast London, where Dr Seuss books sit alongside piles of DVDs and CDs. "During meeting with the producers, somebody would mention a line and I would have to stop myself from reciting the whole scene for fear that they would assume I was a stalker. I can't quite believe I'm working on the film of it, which is going to be brilliant."

Talbot occupies a unique place in music. He has been playing classical music since the age of four, when he picked up piano and oboe, and has studied at the Guildhall and worked with Michael Nyman. But he has also spent much of his adult life on the road with pop and rock bands, so he can see what the two distinct musical worlds can learn from one another.

Modern classical composers could do with having a pop-style hook to hang a piece on, he claims; and pop and rock musicians could do with learning not to copy what has just been successful. "The famous statement about classical music is that it's 10% inspiration and 90% perspiration. I beg to differ. Having worked with all these pop musicians, I've realised that the initial inspiration is all-important. Too much concert music is based on technique and no idea. And pop music should try and appreciate originality a bit more."

Talbot is currently preparing for his contribution to the Proms: a piece for the National Orchestra of Wales called Sneaker Waves performed on September 2. "That's another lifetime dream come true. I spent my youth queuing to get in and daydreaming that one day, I might write a piece for the Proms myself. For a classical musician growing up in London, the Proms is the be-all and end-all; the greatest music festival in the world."

At the age of nine, Talbot wrote his first piano piece. ("It was rubbish, don't get carried away with praise about precociousness.") A few years later, he had a moment of realisation that he wanted to be a composer. "It's all very well deciding that, but the chances of making a living as a composer in this country are fairly remote. It's almost impossible to survive on writing concert music. A commission fee for writing music is nominal. You receive money when it is performed, but when you've spent six months writing your magnum opus string quartet and it gets performed in a village hall with 200 seats - once - that doesn't amount to much."

Talbot survived by diversifying. Much of his music has been written in dank dressing rooms with water dripping from the ceiling in-between sound checks for pop concerts. "My first big commission - a 45-minute orchestral piece - was written on the back of tour buses. It teaches you courage under fire and it's the opposite of sitting in an attic with a quill, waiting for the muse to descend. I would find that an arid and sterile environment in which to work. The isolation approach is very lonely and, dare I say it, rather boring."

Of his record collection, Talbot is not proud. Van Halen and Aerosmith jostle for space alongside Mendelssohn and Vaughn Williams, and there are even albums that combine the two. "My wife bought me a record player recently and I was very excited to dig out all my old teenage albums until I saw what they were," he says. "I was really into Yes. I was hugely into War of the Worlds by Jeff Wayne. The bit that always got me is when they talk about the noises on the railway tracks. We lived by railway tracks in Mitcham and I lay awake at night listening to the spooky noises railway tracks make, so when I heard those noises turned into a piece of music I thought it was for me in particular. Also its narrator was Richard Burton, and he was my hero. I would watch The Medusa Touch with a pen and paper so that I could use some of the choice rude lines he came out with at opportune moments. But people like Yes and Jeff Wayne were trying to achieve the unachievable: to write a rock symphony. It simply cannot work. I don't know whose fault the whole thing is. I guess the Who are partially to blame."

Mahler, Shostakovich and Stravinsky are among Talbot's favourite composers, and he discovered modern composers such as John Adams and Steve Reich at the age of 18. "It was an angst-ridden teenage thing of liking that rather overwrought music," he says. "I remember going to see a Mahler piece at the Royal Festival Hall and getting terribly over-excited and weeping. I thought that was what you were meant to do; that if you didn't leave the concert in tears then you should ask for your money back."

It is the world of soundtracks, however, that Talbot sees as the most vital field of modern composition. "Michael Danner's score for The Ice Storm is just amazing. Carter Burwell, who writes the Coen brothers' music, is brilliant, as is Thomas Newman, who wrote the music for American Beauty and Road to Perdition. The general music scene of the last few years has been pretty piss-poor. The only place to hear amazing, innovative music has been the cinema. You can see that by the fact that John Williams had to create a score as brilliant as Catch Me If You Can in order to keep up. We are in a soundtrack golden age."